ACT Mud Floors flashcards

33 cards. Read the term and the definition here. The deck at the top of this page is optional.

Standard Proctor Test

ASTM D698 test determines maximum dry density and optimum moisture content of soil; used to set field compaction requirements for subgrade.

Proof Rolling

A loaded truck or roller passes over subgrade to identify soft or yielding areas; deflection indicates need for additional compaction or replacement.

USCS Soil Classification

ASTM D2487 groups soils by particle size and plasticity; helps determine suitability for subgrade, with organic and expansive clays requiring treatment.

Subgrade Compaction Requirement

Subgrade must be compacted to at least 95% of maximum dry density per Standard Proctor (ASTM D698) unless project specifications require higher.

Field Density Test

Nuclear gauge (ASTM D6938) or sand cone (ASTM D1556) measures in-place density and moisture; results compared to Proctor to verify compaction.

Expansive Soil Treatment

Highly plastic clays (CH) require lime or cement stabilization or a minimum 4-inch gravel base to prevent volume change and floor cracking.

Frost-Susceptible Subgrade

Frozen subgrade must be thawed and compacted before mud floor placement; frost heave can cause uneven settlement and cracking.

Subgrade Elevation Tolerance

Subgrade must be graded to ±0.05 ft (±15 mm) of design elevation to ensure uniform mud floor thickness and proper drainage.

Mud Floor Mix Proportion

Typical mix: 1 part Portland cement to 3 parts sand by weight, with water-cement ratio 0.45–0.55 for workability and strength.

Sand Gradation for Mud Floor

Sand must conform to ASTM C33, be clean and well-graded, with fines passing #200 sieve not exceeding 5% to avoid strength loss.

Water Quality for Concrete

Potable water free of oils, acids, and organic matter is suitable; ASTM C1602 provides acceptance criteria for mixing water.

Hydrated Lime in Mud Mix

Up to 10% hydrated lime by cement weight can improve workability and reduce cracking; do not add extra water for flow.

Fiber Reinforcement

Polypropylene or glass fibers at 0.1–0.3% by volume reduce plastic shrinkage cracking in mud floors.

Mud Floor Compressive Strength

Target 28-day compressive strength is 2,500–3,500 psi (17–24 MPa) for typical mud floor applications, tested per ASTM C39.

Slump for Mud Floor

Slump should be 4–6 inches (100–150 mm) for placement by chute or buggy; excessive slump reduces strength and causes segregation.

Calcium Chloride Accelerator

Do not use in mud floors; it can cause corrosion of reinforcement and efflorescence, and may affect finish appearance.

Bond Coat Application

Apply cement slurry or latex bonding agent over prepared subgrade immediately before placing mud mix to ensure proper adhesion.

Placement Bay Width

Place mud in strips or bays not exceeding 10 ft (3 m) wide, alternating placement to minimize cold joints and improve workability.

Consolidation of Mud Mix

Use mechanical vibrator or jitterbug to consolidate; avoid over-vibration which causes segregation and weak surface.

Screeding Mud Floor

Strike off to required elevation using a screed guided by edge forms or laser screed; ensures uniform thickness and level surface.

Bull Floating

Immediately after screeding, use a bull float to embed aggregate and remove high spots; do not trowel while bleed water is present.

Construction Joints

Plan joints at predetermined locations; use keyed joints or dowels for load transfer; avoid cold joints by continuous placement.

Installation Temperature Range

Ambient and subgrade temperature must be between 40°F (4°C) and 90°F (32°C) during placement and curing for proper set.

Curing Duration

Keep concrete moist for at least 7 days (or 3 days for accelerated mixes) per ACI 308; use wet burlap, curing compound, or plastic sheeting.

Moisture Vapor Emission Rate

MVER should be ≤3 lb/1000 ft²/24h (ASTM F1869) before applying floor coverings; excess requires mitigation.

Relative Humidity Testing

In-situ RH inside slab should be ≤75% (ASTM F2170) before installing moisture-sensitive flooring; test at proper depth.

Drying Time per Inch

Allow approximately 30 days per inch of slab thickness for normal-weight concrete to dry to acceptable moisture levels before covering.

Vapor Retarder Requirement

A vapor retarder (ASTM E1745) beneath slab is required to prevent moisture migration from subgrade and reduce MVER.

Floor Flatness (FF) Number

FF per ASTM E1155 quantifies surface flatness; typical mud floor minimum FF 25, higher for critical areas.

Floor Levelness (FL) Number

FL per ASTM E1155 quantifies levelness; typical minimum FL 20 for mud floors, higher for very flat floors.

Straightedge Tolerance

Maximum deviation of 1/8 inch in 10 feet (3 mm in 3 m) from a straightedge for standard floors; check per ASTM E1155.

Surface Finish Types

Common finishes: troweled (smooth), broom (non-slip), or exposed aggregate; specify per project requirements and use.

Compressive Strength Testing

Cast cylinders per ASTM C31 and test per ASTM C39 at 7 and 28 days; acceptance requires strength ≥ specified.